Was the TV on before the box was restarted? That needs to be done to make sure the box to recognize the TV. What did you mean by restarted? Powering off, then on again may not do it. That only cuts off the panel lights and outputs. Unplugging and replugging or a red button or software reset is required to make sure the box finds the powered on TV when booting up. There have been problems with Genie's having to do be reset with the TV on if the TV is ever turned off but HR24s are more likely to have a problem with the HDMI cable. Try a different cable.